Over the past 10 years, water and air quality issues relating to the swine industry have been a public concern in the United States. Fairly or not, strong opposition by the general public and many environmental groups to new swine facility construction or renovation has prompted the United States Environmental Protection Agency (EPA) to enact, through state agencies such as the Department of Natural Resources (DNR), stringent, and increasingly limiting, construction, disposal, and emission standards. These new guidelines have merit in what they are trying to achieve—cleaner air and water, with better construction practices to ensure a minimal risk of contamination to the environment. However, the overall effect of these new regulations has been to cause some states to put a moratorium on any new swine facility construction, and further has caused many growers to rethink their expansion plans. Industry leaders estimate the value of pork production in Iowa alone is $12 billion. Significant declines in pork production would represent a considerable loss to the economy in terms of activities involved directly or indirectly with pork production. The new DNR regulations may guide the direction of the future of the swine industry, but they do not address existing sites where urban sprawl and real estate concerns for property owners near facilities have caused disharmony between producers and urban residents.
Currently, there are many technologies dealing with odor control. Some deal with application methods, such as manure injection below ground. A few address the issue of open pits versus covered pits. Others deal with composting of mortalities and the installation of windbreaks.
While these prior art technologies have enjoyed some success and have been used or at least experimented with in the past, they do have some drawbacks.
First of all, the direct injection of manure below ground is an efficient way to control runoff and potential water contamination but falls short in the odor this process creates during the 24- to 48-hour soil saturation period during application.
Secondly, composting is a good way to deal with disposal of mortalities, but it is a small percentage of the odor produced by a swine facility.
Thirdly, windbreaks of growing trees are either very expensive or have very long lead times until they become optimal in their performance and may alter the airflow dynamics of the site. As a result, effective and efficient ventilation may be compromised.
Fourthly, pit additives are costly and vary greatly in their performance. Some additives may alter the water chemistry and change the composition of the manure. Changing this composition would affect the elements of the manure management plan.
Experimentation with the natural bio-filtering may cause clogging and sealing of the filtering medium. The apparatus demands a great deal of site preparation and ground work and is labor intensive during maintenance and replacement of the filtering medium.
Adaptation of industrial scrubbers to address the odor issue requires the addition of input energy and water into the system. The addition of water may dilute the manure in the pit if returned to the pit. This would change the composition of the manure and affect the fertilizer value of the manure. Efforts to recycle the water from the scrubber are currently complex and costly.
Consequently, there exists a need for improved methods and systems for reducing the undesirable effluent from swine production facilities.